The Distributed Lambda Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's Lambda Model; Assessment of Orofacial Gestures

Mohammad Ali Nazari (1, 2) , Pascal Perrier (1) , Yohan Payan (3)

1 GIPSA-MAGIC - GIPSA - Machines parlantes, Gestes oro-faciaux, Interaction Face-à-face, Communication augmentée
2 Department of Mechanical Engineering
3 TIMC-IMAG-GMCAO - Gestes Medico-chirurgicaux Assistés par Ordinateur

Purpose: The authors aimed to design a distributed Lambda model (DLM), which is well-adapted to implement three-dimensional (3-D) Finite Element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the Lambda model along the muscle fibers, together with the passive properties of muscle tissues in the 3-D space. The muscle element was first assessed using simple geometrical representations of muscles in form of rectangular bars. Then, it was included in a 3-D face model, and its impact on lip protrusion was compared with the impact of a Hill-type muscle model. Results: The force-length characteristic associated with the muscle elements matched well with the invariant characteristics of the Lambda model. The impact of the passive properties was assessed. Isometric force variation and isotonic displacements were modeled. The comparison with a Hill-type model revealed strong similarities in terms of global stress and strain. Conclusion: The DLM accounted for the characteristics of the Lambda model. Biomechanically no clear differences were found between the DLM and a Hill-type model. Accurate evaluations of the Lambda model, based on the comparison between data and simulations, are now possible with 3-D biomechanical descriptions of the speech articulators because to the DLM.

Mots clés: Biomechanical orofacial model.; Equilibrium Point Hypothesis; Feldman's Lambda Model; Muscle active force; Muscle passive force; Finite Element Method; Biomechanical orofacial model; Speech motor control

Domaines: Ingénierie biomédicale; Biomécanique [physics.med-ph]; Biomécanique [physics.med-ph]; Neurosciences; Sciences cognitives; Linguistique; Linguistique

Mohammad Ali Nazari, Pascal Perrier, Yohan Payan. The Distributed Lambda Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's Lambda Model; Assessment of Orofacial Gestures. Journal of Speech, Language, and Hearing Research, 2013, 56 (6), pp.1909 - 1923. ⟨10.1044/1092-4388(2013/12-0222)⟩. ⟨hal-00924545⟩